Mashed purple sweet potatoes with a savory herb butter are an easy, comforting yet nutritious and stunning side dish!

Mashed purple sweet potatoes in a serving bowl with herb butter sauce and flaky sea salt.
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These Stokes purple sweet potatoes are downright striking in color and have won my heart with their appearance alone.

I’ve become so obsessed with them over the last couple of years there’s seldom a different kind of potato in my house any more.

After making these roasted purple sweet potatoes which have the most amazing crispy edges and soft tender centers and these crispy oven baked purple sweet potato fries, I wanted to go another route with this purple sweet potato recipe.

So, mashed it was.

I took a similar approach with the butter (ghee actually) herb sauce so the flavors are quite comparable in the two recipes.

But, this mashed version brings a comfort food vibe that only mashed potatoes can.

If the traditional American dinner were to take a 90 degree turn away from sketchy boxes of powdered mashed potatoes towards health and nutrition, these mashed purple sweet potatoes would be the result.

Stokes purple sweet potatoes, one whole, one cut in half on a wooden board.

Whether you’re using the more commonly found purple sweet potato in the U.S. named the “Stokes” purple sweet potato (usually with a Frieda’s produce tag on them in stores) or, a Japanese sweet potato (also called an Okinawan potato), this mashed potato recipe will not disappoint.

And it’ll work with any of those varieties.

I go through the difference between all these purple potatoes in my roasted purple potato recipe linked above.

If you’re finding yourself confused by the nuances in nomenclature, go check out that post.

Sliced Japanese purple sweet potatoes in a pot with cold water before boiling.

HOW TO MAKE MASHED PURPLE SWEET POTATOES

While it may not be as easy as making a box of powdered mashed white potatoes (insert eye roll here), these creamy mashed Stokes purple potatoes are pretty darn simple.

To start, boil the potatoes until fork tender and “mashable”.

Cut the purple potatoes into chunks and add them to a large pot filled with cold water.

Bring the pot to a boil then cover and keep at a low boil until the potatoes can easily be pierced with a fork or knife. This will take about 15-20 minutes.

While the potatoes boil, make the easy butter herb sauce by combining the butter or ghee in a small sauce pot with the garlic and minced herbs.

Over a low-medium heat, let the butter simmer for about 5 minutes until melted and the aromatics have infused into it. Turn off the heat and set aside.

Drain the potatoes once they’re tender and return them to the pot. Add the milk, salt and pepper and mash until creamy.

Pour in most of the herb butter sauce reserving some for serving and stir into the mashed purple potatoes.

Serve hot with the remaining sauce and garnish with flaky sea salt.

Making an herb butter sauce with ghee, fresh sage, thyme and garlic in a small pot.

DO I NEED TO PEEL THE PURPLE POTATOES?

This is totally up to you and your preference when it comes to mashed potatoes.

I used two large purple potatoes for this recipe and left one with the skin intact for some texture in the finished dish while peeling the other.

If you like your mashed potatoes totally creamy, peel the potatoes. If you’re down for some texture, leave it on. Sweet potato skin has a bit more texture than Yukon gold or red skin potatoes (which are great for a creamy mash) so decide accordingly.

I tend to like texture in dishes, even mashed potatoes (like these garlic Greek yogurt smashed potatoes).

Mashed purple sweet potatoes in a pot with a potato masher and herb butter sauce.

HOW DOES THIS TASTE COMPARED TO REGULAR MASHED POTATOES?

Japanese purple sweet potatoes have a sweet candy-like depth of flavor unrivaled by any white potato.

Don’t get me wrong, I love some roasted pesto potatoes or roasted peri-peri potatoes with those little white or tri-color potatoes but purple sweet potatoes are on a completely different level flavor wise.

Being a sweet potato, they’re obviously similar to traditional orange sweet potatoes in flavor but there’s more “candy” taste than squash taste if that makes sense.

That’s probably the best way I can describe the difference between purple sweet potatoes and regular sweet potatoes.

Imagine a scale where on the left is a pumpkin/winter squash and on the right is a Jolly rancher, purple sweet potatoes err more to the right whereas orange sweet potatoes are just left of center.

That’s why I love adding the easy herb butter sauce to this purple mashed potato recipe, it adds back a bit of savory flavor to complement the sweetness.

I also use this garlic herb butter trick with mashed rutabaga, it complements the “sweeter” root vegetable wonderfully.

On that note, it’d go great over this mashed yuca as well since that’s also a root vegetable with a subtle sweetness to it.

Purple sweet potatoes mashed in a pot with a spoon.

CAN I MAKE THIS RECIPE SWEET?

If you’re a person who loves sweet potato pie at Thanksgiving going the sweet route with this healthy purple sweet potato mash might be your thing.

Instead of the herb butter, try butter, maple syrup and some pecans (candied or not).

I’ve never loved “sweet” sweet potato recipes so I don’t tend to lean in that direction too often.

But I do love simplicity.

Instead of taking the time to mash them, I’ll sometimes just bake the purple sweet potatoes whole in the oven, split in half, drizzle some coconut oil and maple syrup then finish with Himalayan sea salt.

That’s my version of “sweet” purple sweet potatoes and it’s not a bad option either for a more hands off approach than mashing.

Creamy purple mashed sweet potatoes in a dish with herb butter sauce and sea salt.

WHERE TO FIND PURPLE SWEET POTATOES

It’s thankfully getting easier and easier to source these beauties.

Most Whole Foods, natural food stores and even Trader Joe’s will have either Stokes purple sweet potatoes or Japanese purple sweet potatoes these days.

I long for the day Shoprite or Publix stocks these gems!

You can also often order them online from produce shipping companies if those stores aren’t in your area.

WHY PURPLE SWEET POTATOES?

So they’re not ubiquitous, why even bother seeking out purple sweet potatoes for this mash?

Let me tell you about my ‘lil frands…

These bright purple beauties are packed with added nutrition compared to regular potatoes.

Anytime you see that bright purple color or a deep red color in any type of produce, it’s due to something called anthocyanins.

I’ve talked a lot about the benefits of anthocyanins in tart cherries (like in these tart cherry cookie dough bars and this turmeric salmon with cherry sauce) and the same apply to purple sweet potatoes.

Anthocyanins are antioxidants that help fight inflammation and boost the immune system.

Purple sweet potatoes have three times more anthocyanins than blueberries! (source)

Purple sweet potatoes and yams are also high in fiber (there’s 4g of fiber per 100g serving) and vitamin C.

Furthermore, there are many studies showing that the flavanoids (fancy name for plant chemicals or phytonutrients) in purple potatoes are helpful in maintaining a normal blood sugar.

This is likely due to their low score on the glycemic index.

Purple sweet potatoes score a 24 on the GI index.

For context, white potatoes score 111 and regular sweet potatoes 54.

One of the many reasons I now almost always grab purple sweet potatoes in place of any other in the store.

Easy mashed purple potatoes with herb butter sauce in a bowl with a serving spoon.

WHAT TO SERVE WITH MASHED PURPLE YAMS

Plain and simple, serve these striking purple mashed potatoes with anything you’d normally serve mashed potatoes with.

For a doubly purple dinner, how about some blueberry balsamic BBQ turkey legs?

Or, an easy skillet pork chop?

They’d make a great complement to rosemary garlic flank steak with blackberry sauce too.

They’re even great with seafood like this simple baked wild sockeye salmon recipe.

You can use them as the base of a buddha bowl type of meal as well and take things in the vegetarian direction.

If I had my choice, I’d pick a purple sweet potato mash over rice, quinoa or any other grain base all day long!

HOW TO STORE PURPLE MASHED POTATOES

Like any other mashed potato recipe, these will store fine in the fridge or freezer.

For the freezer, use a sealable bag and press all the air out of it when sealing. They’ll last for a quite some time this way.

I’ve kept frozen mashed potatoes for up to half a year in the freezer before.

It’s great to keep them on hand like this and be able to pull out for an easy side dish with dinner.

Or, even to use in a recipe like sweet potato raisin bread or whole wheat sweet potato banana muffins (for a purple variation on those recipes).

Spoonful of purple mashed sweet potatoes.

Since purple sweet potatoes have become a staple in my house lately, I’ll probably be sharing a few more ways we love enjoying them in the upcoming months.

They’ll all be easy recipes like purple sweet potato fries, simply baked purple potatoes and more.

They’re just too good of an ingredient to gloss over!

MORE SWEET POTATO RECIPES TO TRY:

Maple baked sweet potato tots
Sweet potato waffles (trying these ASAP with purple sweet potatoes!)
Sweet potato cookies
Sweet potato bran muffins
Turkey sweet potato skillet

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4.27 from 41 votes

Mashed Purple Sweet Potatoes

Servings: 4 servings
Prep: 10 minutes
Cook: 20 minutes
Total: 30 minutes
mashed purple sweet potatoes
Mashed Japanese or Stokes purple sweet potatoes with savory herb butter are an easy, comforting, nutritious and stunning side dish!

Ingredients 

  • 1.5-2 pounds purple sweet potatoes, Stokes or Japanese
  • 2 ounces ghee/butter/plant-based butter alternative
  • 2 cloves garlic, minced
  • 1/4 cup minced fresh herbs, sage, thyme, chives, etc.
  • 1/2 cup milk or milk alternative, unsweetened and plain if plant based
  • salt and pepper to taste

Instructions 

  • Wash and peel sweet potatoes (*see note) and cut into large chunks. Place in a large pot and cover with cold water. Bring to a boil on the stove-top, cover and cook until fork tender, about 15-20 minutes.
  • While the potatoes boil, combine the butter or ghee in a small sauce pot over medium-low heat. Add the garlic and herbs and let simmer for a few minutes until butter is completely melted and flavors of the herbs have infused into it. Set aside.
  • Drain the potatoes once ready and place them back into the pot. Add the milk, salt and pepper and mash until creamy.
  • Pour the melted butter herb sauce (reserving some for serving) onto the mashed potatoes and stir to combine.
  • Serve with the additional butter herb sauce and finish with some flaky sea salt.

Notes

*It’s not necessary to peel the potatoes just wash well if you like the skins in your mashed potatoes.

Nutrition

Serving: 1SERVINGCalories: 403kcalCarbohydrates: 52gProtein: 8gFat: 19gSaturated Fat: 12gPolyunsaturated Fat: 6gCholesterol: 51mgSodium: 227mgFiber: 8gSugar: 15g

Nutrition information is automatically calculated, so should only be used as an approximation.

Additional Info

Course: Side Dishes
Cuisine: American
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Founder and Writer at Running to the Kitchen | About

Gina Matsoukas is an AP syndicated writer. She is the founder, photographer and recipe developer of Running to the Kitchen — a food website focused on providing healthy, wholesome recipes using fresh and seasonal ingredients. Her work has been featured in numerous media outlets both digital and print, including MSN, Huffington post, Buzzfeed, Women’s Health and Food Network.

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12 Comments

  1. 2 stars
    I love purple sweet potatoes, and I thought this recipe would add some awesome flavor pairings. I tried it with sage and ghee, and I found it covered up the flavor of the potato far more than I cared for. (I’m not used to cooking with sage, but I did use the ghee sparingly as I know it is strong).